'Plant Breeding: Sustaining the Future' Abstracts of the XVIth EUCARPIA Congress, Edinburgh, Scotland, 10-14 September 2001 GENETIC ANALYSIS OF FLOWERING TIME IN A SPRING/WINTER BARLEY CROSS A.M. CASAS, E. IGARTUA, F.J. CIUDAD, M.P. GRACIA, J.L. MOLINA-CANO, J.L. MONTOYA, I. ROMAGOSA Estación Experimental de Aula Dei (CSIC), Department of Genetics and Plant Production, PO Box 202, 50080 Zaragoza, Spain

Barley adaptation to Mediterranean conditions is greatly dependent on phenology.    We present a study of a barley doubled haploid population –Beka/Mogador- whose parents differ at all four major loci controlling photoperiod and vernalization responses in barley (sh, sh2, Ppd-H1 Ppd-H2).  A set of 120 doubled haploids was evaluated for development traits in the field, and under controlled temperature and photoperiod conditions.  A map with 154 well spaced markers (AFLP, SSR, RAPD, RFLP), spanning 80cM, and providing good coverage of the 7 chromosomes was produced.  The four regions cited above explained between 75% and 85% of heading date variance in field trials, and between 63 and 85% of developmental traits measured under controlled conditions, including variance due to epistatic interactions between several pairs of regions.